Bats

Bats are flying creatures that attack players. They can be found almost everywhere. They have 50 hp at level 1, deal 30 damage to a player who has 0 defense skill, but can be further lowered by buying defense points. Bats drop 2 coins when killed.

If you put on a bat repellent, bats won't be able to see you, so they won't attack you. Note that it is possible to go up to the limit of a game map by "riding" bats!